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Plurality criterion is a voting system criterion devised by Douglas R. Woodall for ranked voting methods with incomplete ballots. It is stated as follows:
This criterion is trivially satisfied by rank ballot methods which require voters to strictly rank all the candidates. The Borda count is usually defined in this way.
Woodall has called the Plurality criterion "a rather weak property that surely must hold in any real election" opining that "every reasonable electoral system seems to satisfy it." Most proposed methods do satisfy it, including Plurality voting, IRV, Bucklin voting, and approval voting.
Among Condorcet methods which permit truncation, whether the Plurality criterion is satisfied depends often on the measure of defeat strength. When winning votes is used as the measure of defeat strength in methods such as the Schulze method, Ranked Pairs, or Minimax, Plurality is satisfied. Plurality is failed when margins is used. Minimax using pairwise opposition also fails Plurality.